从上往下打印二叉树

 public void cengOrder(Node node){
        if(node == null) return;
        Queue<Node> queue = new LinkedList<Node>();
        queue.add(node);
        while(!queue.isEmpty()){
            
                Node temp = queue.poll();
                System.out.println(temp.data);
                if(temp.left!=null) queue.add(temp.left);
                if(temp.right!=null) queue.add(temp.right);
            
        }
    }